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Stencil Cleaner



Stencil Cleaner | 26 March, 2002

I am looking a stencil cleaner machine. My co. is ISO 14000 certified ans using no-clean process. I am looking at various options. 1) Water cleaned Vs solvent 2) Ultrasonics Vs spraying.

I had also the intention to use this machine to wash wavesolder pallets and misprint solder paste.

Any inputs is welcome.

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Mike Konrad


Stencil Cleaner | 26 March, 2002

There are two basic technologies to choose from:

1. Ultrasonic 2. Spray-in-air

Makers of ultrasonic stencils include:

Aqueous Technologies (that�s us): PMR: JNJ Industries: SmartSonic

Makers of spray-in-air systems include: EMC: Austin America:

Make your choices as follows:

Technology: Ultrasonic or Spray-In-Air

There are differences between ultrasonic and spray-in-air systems. Manufacturers will provide you with the benefits of their technologies. We use to manufacture spray-in-air systems but changed to ultrasonic technology about three years ago. We believe that ultrasonic technology is superior to spray-in-air with respect to cleaning ability and stencil safety. Other companies will disagree.

Discharge / Environmental: Filtered Drain, Evaporation, or Closed-Loop

With regards to environmental compliance, you have three choices:

1. Choose a system with an adequate filtration system and send effluent to drain.

2. Connect a stencil cleaner to an evaporator rather than connecting it to a drain. Most, if not all, manufacturers sell evaporators.

3. Choose a machine that is closed-loop (no drain). I prefer this method as this eliminates an evaporator and reduces both equipment purchase costs and operational costs.

Labor or Automation Semi-Automatic or Fully-Automatic

Where are you willing to spend your money? Semi-automatic stencil cleaners are actually faster than fully-automatic stencil cleaners. On the down side, they require an operator to become part of the process. Fully-automatic cleaning systems provide wash, rinse, and dry cycles (check with each manufacturer to verify their level of automation). Although the entire process is a little slower than semi-automatic machines, an operator simply loads a stencil and, presumably, is free be productive in other areas.

Prices for said machines vary widely. Semi-automatic machines range from $ 10,000 up to $ 25,000. Fully automatic machines (wash, rinse, dry) range from $ 25,000 to $ 45,000.

Search SMT-Net�s archive under �stencil cleaners� and you will find perhaps more information than you wanted!

I hope this helps.


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Stencil Cleaner | 27 March, 2002


We have a Cleaing machine which is Germany product. This cleaning machine is using water base (detergent) and is a spray type. You can visit our web-side at for more information.

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Stencil Cleaner | 28 March, 2002

No-clean fluxes seem harder to clean from stencils [squeegees and tools] than water wahable fluxes. Do you see that also? If so, what is the impact on stencil cleaner operation?

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Mike Konrad


Stencil Cleaner | 28 March, 2002

Hi Dave,

No-clean paste is more difficult to remove in post-reflow cleaning applications. In stencil, misprint and tool cleaning applications however, no-clean paste poses no extra degree of cleaning difficulty.

There are few special requirements of a stencil cleaning system. Basic requirements are:

The ability to handle a chemistry (required for no-clean paste removal).

A filtration system, although not required, will extend the life of the wash solution thereby lowering operational costs.

If using a spray-in-air cleaning system, special consideration should be given to the chemical selection. Only non-foaming chemicals can be used due to the agitation of the wash-solution. This is not a concern in ultrasonic or other immersion cleaning systems as they do not agitate the wash solution.

For misprint cleaning applications, the machine should have excellent rinsing capabilities. Rinsing, although desired for stencil cleaning, is absolutely critical in misprint applications. Under no circumstances should wash solution be allowed to stay on a misprinted board. Thorough rinsing with DI water is recommended.

The only machines not compatible with no-clean pastes are water-only machines.

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Stencil Cleaner | 28 March, 2002

Hello Dave,

Water Washable (Organic Acid, OA) post solder flux residue is designed for cleaning in plain water without cleaning chemical additives. The real advantage of water washable flux was that it cleaned in plain water without additives � no chemicals to manage in the wash or waste stream. However, when OA solder paste was first introduced, the virgin solder paste did not easily clean in plain water. What advantage was a chemical-free post solder cleaning process if the presolder cleaning of stencils and misprints required chemical additives? To correct the problem, most solder paste manufacturers have added a small amount of surfactant (detergent) to their formula to assist in cleaning the raw solder paste from stencils and misprints. The surfactant is polymerized in the reflow oven and has little if any effect downstream. Technically, one still needs a chemistry to clean raw OA solder paste; it is just invisible to the user. True, this is kind of a �smoke and mirrors� solution, but it has satisfied the users to this point.

With RA, RMA and rosin-based No-clean solder pastes, rosin is the primary contaminant and chemical additives are needed in both the pre and post solder cleaning applications of raw solder paste and flux residues. Chemicals are also required for cleaning synthetic no-clean solder pastes. Unlike OA solder paste, not just any surfactant will work. This is why the chemistry is the most important part of the cleaning process. The chemistry also has the biggest impact on the cleaning operation.

The chemistry determines the reaction with the contaminant, environmental impact, user safety (health, fire, explosion potential), operational cost (consumption and heat requirements), presence of odors and vapors, cleaning cycle time, ability to clean different contaminants, maintenance requirements, special storage, and transportation requirements. The chemistry will also dictate many of the cleaning machine specifications such as heating, venting, filtration, construction material, special pump seals, plumbing and costly installation to properly isolate equipment using a low-flashpoint chemistry.

So, to answer your question: Yes, I also see that. And, it has a huge impact on the stencil cleaning operation.

Best regards, Bill Schreiber Smart Sonic Corporation

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